According to a new study, climate change is threatening zooplankton in the Arctic. The huge group of different organisms could stay longer in the depths in the future, according to the journal "Nature Climate Change". "This would have fatal effects on the entire ecosystem, including seals, whales and polar bears," says Hauke Flores from the international research team headed by the Alfred Wegener Institute based in Bremerhaven, according to a statement.
Zooplankton are microorganisms that are found all over the world and form the basis of food for countless sea creatures. These organisms include small crustaceans and rotifers.
In many cases, according to the research team, the zooplankton approach the water surface under cover of darkness to feed. "The most violent synchronous mass movement of organisms on the planet takes place in the oceans every day," says Flores.
If it is too bright without an ice cover, the plankton stays in the depths
In the polar regions, on the other hand, the zooplankton migrate seasonally: when it is light for months in summer, the zooplankton remain permanently in the depths. Some of the zooplankton only approach the water surface in the dark in winter.
According to the study, if the sea ice melts as a result of climate change, sunlight can penetrate deeper and deeper into the ocean - even in the otherwise dark season. The zooplankton orientate themselves to the light conditions and change their behavior as a result: the tiny animals will stay longer in the depths in the future.
"In the future, in a warmer climate, the ice will form later in the fall, resulting in less ice algae production," explains Flores. "In combination with the later ascent, this can lead to more frequent food shortages in zooplankton in winter."
The study shows that the chances of survival for zooplankton in the Arctic are becoming increasingly worse. This development has consequences for the entire ecosystem. If there is less zooplankton, many fish will have less to eat and, in the end, whales, seals and polar bears will also have a problem.
In order to slow down the process, the 1.5 degree target must be met, the research team appeals. Every tenth degree less warming is important for the ecosystem of the artis.